The present invention is in the field of optical interconnection devices, such as those that may be useful in routing information for communications systems.
U.S. Pat. No. 6,266,176 discloses a device for optical interconnection.
An object of the present invention is to provide a binary (or higher order exponential) optical interconnection using optical fibers to shift beams among various outputs.
In U.S. Pat. No. 6,266,176, an optical interconnection device was described in which multiple light beams bounced repeatedly between a set of spherical mirrors. Each light beam produces a specific spot pattern based on which of the mirrors are visited and how many times. In the original invention, the spots for each beam were shifted by the spherical mirrors, whose centers of curvature were located in different positions. In the present invention, the shifting is accomplished instead by a shifting unit located in an image plane of the spatial light modulator. In this case the shifting unit consists of various optical fibers, each os whose inputs intercepts a given spot and whose output reproduces the spot in a new row or column.
As used herein, the term xe2x80x9cshifterxe2x80x9d shall be understood to mean a shifting unit. As used herein, the term xe2x80x9csourcexe2x80x9d shall be understood to mean any source, structure, article or device either generating or reflecting an optical beam.
In broadest terms, a shifting unit using optical fibers to shift beams among various outputs of the present invention comprises: a shifting entrance plane and a shifting exit plane. The shifting entrance plane comprises at least one row of signal input positions. Each signal input position is adapted to receive an optical beam from a source. The shifting exit plane comprises a respective number of rows of signal output positions. Each signal output position is adapted to output an optical beam received by the shifting entrance plane. Each signal input position of a given row is connected by an optical fiber to a corresponding signal output position. Each optical fiber is the same length as every other optical fiber in the shifting unit
An apparatus for optically shifting signals of the present invention comprises: an auxiliary mirror; a micro-electro-mechanical device (or other spatial light modulator); a shifting unit; a first pair of spherical mirrors; and a second pair of spherical mirrors. The shifting unit comprises: a shifting entrance plane and a shifting exit plane. The shifting entrance plane comprises at least one row of signal input positions. Each signal input position is adapted to receive an optical beam from a source. The shifting exit plane comprises a respective number of rows of signal output positions. Each signal output position is adapted to output an optical beam received by the shifting entrance plane. Each signal input position of a given row is connected by an optical fiber to a corresponding signal output position. Each optical fiber is the same length as every other optical fiber in the shifting unit. Each mirror of the first pair of spherical mirrors has a center of curvature. Each mirror of the first pair of spherical mirrors is positioned such that its center of curvature (or the image of the center of curvature) lies between the auxiliary mirror and the micro-electro-mechanical device. Each mirror of the second pair of spherical mirrors has a center of curvature. Each mirror of the second pair of spherical mirrors is positioned such that its center of curvature lies between the micro-electro-mechanical device and the shifting unit.
In a preferred embodiment of the present invention, the auxiliary mirror, micro-electro-mechanical device lie in one plane, and the entrance and exit of the shifting unit lie in a second plane. In another preferred embodiment of the present invention, the apparatus further comprises at least one optical element disposed between the first and second planes.
A second apparatus for optically shifting signals of the present invention comprises: a micro-electro-mechanical device disposed in a first plane; an auxiliary mirror disposed in a second plane; a shifting unit disposed in a third plane; and a pair of lenses disposed between the shifting unit and the micro-electro-mechanical device. The shifting unit comprises: a shifting entrance plane and a shifting exit plane. The shifting entrance plane comprises at least one row of signal input positions. Each signal input position is adapted to receive an optical beam from a source. The shifting exit plane comprises a respective number of rows of signal output positions. Each signal output position is adapted to output an optical beam received by the shifting entrance plane. Each signal input position of a given row is connected by an optical fiber to a corresponding signal output position. Each optical fiber is the same length as every other optical fiber in the shifting unit.
In a preferred embodiment, the apparatus further comprises at least one optical element disposed between the first plane and the second plane.
A method for optically shifting a signal of the present invention comprises the steps of: modulating an input signal onto an optical beam; passing the optical beam through an apparatus for spatially shifting signals; and down-converting the optical beam to an output signal. The apparatus comprises an auxiliary mirror; a micro-electro-mechanical device; a shifting unit; a first pair of spherical mirrors; and a second pair of spherical mirrors. The shifting unit comprises a shifting entrance plane and a shifting exit plane. The shifting entrance plane comprises at least one row of signal input positions. Each signal input position is adapted to receive an optical beam from a source. The shifting exit plane comprises a respective number of rows of signal output positions. Each signal output position is adapted to output an optical beam received by the shifting entrance plane. Each signal input position of a given row is connected by an optical fiber to a corresponding signal output position. Each optical fiber is the same length as every other optical fiber in the shifting unit. Each mirror of the first pair of spherical mirrors has a center of curvature. Each mirror of the first pair of spherical mirrors is positioned such that its center of curvature lies between the auxiliary mirror and the micro-electro-mechanical device. Each mirror of the second pair of spherical mirrors has a center of curvature. Each mirror of the second pair of spherical mirrors is positioned such that its center of curvature lies between the micro-electro-mechanical device and the shifting unit.
A second method of the present invention for optically shifting a signal comprises the steps of: modulating an input signal onto an optical beam; passing an optical beam through an apparatus for optically shifting signals; and down converting the optical beam to an output signal. The apparatus comprises: a micro-electro-mechanical device disposed in a first plane; an auxiliary mirror disposed in the first plane; a shifting unit disposed in a second plane; and a pair of lenses disposed between the shifting unit and the micro-electro-mechanical device. The shifting unit comprises a shifting entrance plane and a shifting exit plane. The shifting entrance plane comprises at least one row of signal input positions. Each signal input position is adapted to receive an optical beam from a source. The shifting exit plane comprises a respective number of rows of signal output positions. Each signal output position is adapted to output an optical beam received by the shifting entrance plane. Each signal input position of a given row is connected by an optical fiber to a corresponding signal output position. Each optical fiber is the same length as every other optical fiber in the shifting unit.